EFFECT OF MEDIUM ACCESS CONTROL (MAC) ON THE THROUGHPUT OF MULTI-HOP WIRELESS AD-HOC NETWORK

I. Mustapha¹, J. D. Jiya² , B. U. Musa¹

¹Department of Electrical and Electronic Engineering,University of Maiduguri, Nigeria

²Electrical Engineering Programme,Abubakar Tafawa Balewa University, Bauchi Nigeria.

E-mail: ibrahimmassa@yahoo.com,    jibjiya@yahoo.co.uk ,      musa_bu@yahoo.com

ABSTRACT

Medium Access Control (MAC) protocol is the main element that determines the efficiency in sharing the limited communication bandwidth of the wireless channel in IEEE 802.11 wireless networks. This paper, investigate the effect of MAC on throughput of multi-hop wireless ad-hoc network. A Markov chain is used to model a collision avoidance MAC protocol for multi-hop wireless ad-hoc networks. In the models, two fundamental issues in MAC, i.e., collisions and spatial reuse in terms of persistent probability, sensing range and back-off time mechanism were considered. Simulation results show that collision avoidance MAC mechanism such as persistent probability; sensing range and back-off time have significant effects on the performance of multi-hop wireless ad hoc networks. The effects of these MAC mechanisms were influenced by the number of neighbors, transmission range and length of data frame. It is observed that throughput increases with increase in persistent probability and also effect of sensing range on the throughput is weakening when the transmission range is short. Similarly throughput increases with increase in sensing range and back-off time when number of neighbors increases. On the other hand throughput decreases with increase sensing range and back-off time when transmission range increases

Keywords: Mobile ad hoc networks, medium access control, back-off algorithm, RTS/CTS Mechanism, Markov Chain.